Apparatus for vibrating concrete pipe forms



March 15, 1955 BUTLER 2,703,916

APPARATUS FOR VIBRATING CONCRETE PIPE FORMS Filed Nov. 6, 1950 3 Sheets-Sheet 1 FIG. I. I2

INVENTOR ADOLF G. BUTLER 747, /QJMW ATTORNEYS March 15, 1955 A. s. BUTLER 2,703,916

APPARATUS FOR VIBRATING CONCRETE PIPE FORMS Filed Nov. 6, 1950 3 Sheets-Sheet 3 FIG.76. FIG. 7.

INVENTOR ADOLF G. BUTLER 07 M, vii... AM

ATTORNEYS United States Patent M APPARATUS FOR VIBRATING CONCRETE PIPE FORMS Adolf G. Butler, Hawthorne, Calif., assignor to American Pipe and Construction Co., a corporation of Delaware Application November 6, 1950, Serial No. 194,357

Claims. (Cl. 2530) This invention has to do with the making of what is called centrifugally spun concrete pipe. Such pipe is made by introducing a concrete mixture into a form and rotating the form at a speed sufficient to retain the concrete in the form and compact it.

In order to obtain extremely high-strength concrete pipe the concrete mixture, or mix, as it is called, should be relatively dry. Such mixes are difficult to properly compact by centrifugal force alone. I am aware that efforts have been made to assist the centrifugal action by employing a roller operating against the inner surface of the mix and by employing means for vibrating the form. My invention is concerned chiefly with means for vibrating the form.

It is an object of this invention to provide improved apparatus for compacting the concrete in the making of centrifugally spun concrete pipe and to produce an improved product.

It is a particular object of the invention to provide a novel method and apparatus for imparting high velocity vibrations to a pipe form as the same is rotated in the making of centrifugally cast pipe.

A further object is to provide apparatus for setting up desired vibrations in a rotating pipe form which permits access to the interior of the pipe form for the purpose of filling the same and employing rolling, troweling, and other equipment therein.

Another object is to provide novel apparatus for mounting a vibration-inducing wheel to yieldably hold the same in engagement with the periphery of the pipe form.

A still further object is to provide apparatus for inducing vibrations in a rotating pipe from one end thereof to the other.

Yet another object is to provide means for variably vibrating a pipe form during rotation thereof.

These and other objects will be apparent from the drawings and the following description.

Referring to the drawings:

Fig. l is a fragmentary and elevational view of apparatus for carrying out the invention;

Fig. 2 is a fragmentary sectional plan view of the apparatus of Fig. 1;

Fig. 3 is an enlarged section on line 33 of Fig. 1;

Fig. 4 is a fragmentary section on line 44 of Fig. 3;

Fig. 5 is a fragmentary sectional view on line 5-5 of Fig. 3

Fig. 6 is a side elevational view, partly broken away, showing another form of apparatus embodying the invention;

Fig. 7 is a section on line 7-7 of Fig. 6;

Fig. 8 is a side elevational view, partly broken away, showing. another form of apparatus embodying the invention; and

Fig. 9 is an end elevational view on line 9-9 of Fig. 8.

More particularly describing the invention, referring first to Figs. 1-5, there is shown a metal pipe form, generally indicated by 11, which is generally cylindrical in shape, having a main cylindrical wall or shell 12 and end rings 13 thereon. In the conventional concrete pipe form the shell 12 is split longitudinally and bolted together for the making of the pipe so that once the pipe has been formed and set sufficiently, the form may be parted to remove the pipe. conventionally the end rings 13 are detachably mounted on the shell 12. However, since this forms no part of the invention, these details of construction have not been shown.

In making centrifugal pipe the form 11 is mounted on wheels 15 and 16, often referred to as trunnions in the art. The wheels 15 are idler wheels journaled in suitable bases 18. The wheels 16 are mounted on a driveshaft 20 journaled in bases 21. The wheels 16 are driven in any suitable manner as by means of a chain 22 which passes around a sprocket wheel 23 on the shaft. The chaincan be driven by a motor (not shown). The end rings 13 are provided with flanges 13 for retaining the form on the wheels.

With the above-described structure it will be apparent that the form 11 can be rotated at desired speeds. In the making of pipe the concrete mix is introduced into the form when the same is rotating and through the action of centrifugal force this mix forms a relatively compact concrete wall, such as that shown at 25 (Fig. 2), against the inner surface of the form.

ln order to provide means for compacting the mix against the wall of the form and for enabling the use of relatively dry mixes which cannot be properly compacted by centrifugal force alone, I provide means for vibrating the form as the same rotates. The means for vibrating the form comprises essentially the provision of vibrator wheels 30 having interrupted peripheral faces which are forced into contact with the rotating form. The form is provided with tracks or reinforcement bands 31 against which the vibrator wheels operate. In the particular embodiment of the invention illustrated in Figs. 1-5 three such wheels 30 and three such bands 31 are shown. The outer two wheels 30 are mounted on one side of the center line or axis of the pipe form being rotated and the center wheel is mounted on the opposite side as is best shown in Fig. 2. The wheels are mounted on beams 34 which can be supported upon any suitable foundation.

Referring to Figs. 35 for the details of construction of the wheel assemblies, each wheel is rotatably mounted in a bracket 35, which includes a bifurcated portion 36 provided with a pin 37. The vibrator wheel is mounted on the pin with a suitable roller bearing 38 between the parts. The brackets 35 are provided with an elongated tubular section 40 which is internally grooved to receive the splines 41 on a torsion bar 42. The ends 40 of the section 40 are rotatably received in pillow blocks 45 secured to a beam 34 which may be of H-shape in cross section, except that in the region of the vibrator wheel assemblies it is shown provided with a bottom plate 34.

The other end of the torsion bar 42 is splined at 47 to a sleeve 48 which is received in a pillow block 49, also mounted on the beam 34. The outer end of the torsion bar carries an arm or lever 51 which is connected to a fluid ram 52 through the medium of a snubber 54. The {Jam is pivotally mounted at 55 upon an anchor mem- The snubber shown comprises a bar 58 pivotally mounted on arm 51 and vulcanized in a body of rubber or the like 59. The latter is vulcanized in a cylindrical casing 60 to which is attached a yoke 61 connected to the piston of the ram.

The ram 52 may be of conventional construction having a fluid inlet connection 63 and a piston therein, the piston rod of which is shown extending at 64. When pressure fluid is admitted to the piston this is effective to force the vibrator wheel into engagement with the band 31 on the form.

Each vibrator wheel has a peripheral surface which is interrupted by a plurality of concave recesses 65 spaced circumferentially by short peripheral sections 66 of the wheel. In the form of the invention illustrated each wheel presents a scalloped peripheral face to the pipe form.

It will be apparent that, when the form 11 is rotated at relatively high speed and the rams 52 are operated to force the vibrator wheels into engagement with the bands 31 on the form, by reason of the interrupted faces of the wheels engaging the form, the form as a whole will be subjected to vibrations of a frequency dependent upon the speed of rotation of the form and the number of recesses in the vibrator wheels. I find that if I adjust these factors so as to produce vibrations of the order of between 10,000 and 20,000 cycles per minute, ex-

oellent results are obtained. It will be apparent that the peripheral portion of the vibrator wheels themselves will necessarily have to be formed of a relatively hard material and these surfaces may be of hardened steel, for example.

I may employ any number of vibrator wheels. Where more than one wheel is used, each wheel may have the same number of recesses therein as shown in the drawings in which case the vibrations induced will be of substantially the same frequency as if only one vibrator wheel were used, but of greater intensity. However, I can produce other frequencies of vibration in the form by using two or more vibrator wheels having different numbers of recesses therein. By so doing I can also produce a plurality of and variable vibration frequencies in the form and also certain beat frequencies all of which may be desirable to effect compacting of the concrete mix since the individual different component particles of the mix may be assumed to be most affected by different frequencies. Thus I also contemplate a method of forming concrete pipe which includes subjecting the rotating form to variable frequencies of vibration and a plurality of frequencies of vibration as well as combining different frequency vibrations to produce beats.

In Figs. 6 and 7 I show another form of apparatus for inducing vibrations in the pipe form which entails the use of wheels or rollers having interrupted peripheral faces. Referring to these figures, 30 generally indicates a foundation upon which are rotatively supported the idler wheels 81 and drive wheels 82 for supporting the pipe form 11. In this form of the invention I show two vibrating wheel assemblies 84. These assemblies each include a supporting column 85 at the upper end of which there is pivotally mounted a vibrator wheel arm 86. The arm includes a rigid or base section 87 and a leaf spring section 88 at the outer end of which the vibrator wheel, here indicated by 89, is journaled as between the uprights 90.

For the purpose of yieldably forcing the vibrator wheel into engagement with the band 31 on the periphery of the pipe form I providea piston and cylinder mechanism or ram 92 which is pivotally mounted on the base at 93, the piston 94 of which is pivotally connected at 95 to the arm 86.

In Figs. 8 and 9 I show another means for vibrat ng a pipe form. Referring to these figures, I show a p1pe form 101, similar to the form 11 previously described, supported upon suitable wheels or trunnions 102 and 103. In this form of the invention I provide a vibrator means, generally indicated by 105 at one end of the p pe form. This is accomplished by providing an end r ng 106 with a spider mounting 107 in the center of WhlCh is mounted the vibrator mechanism, such as an eccentrically weighted shaft 109 driven by a motor. The motor may be an air motor as is conventionally used 1n driving vibrators and the air supply conduit 111 to the motor may be connected to a suitable source of compressed air through the medium of a c onvent1onal o1nt which will permit of rotation of the plpe form wlthout fouling the air hose or conduit 111.

It will be apparent that with the form of the invention as shown in Figs. 8 and 9 the vibrator is located on the axis of the form and serves to transmit v1brat1ons through the special end ring to and throughout the form. It will also be apparent that one end of the form is left open, thereby permitting the introduction of the concrete into the form and the use of suitable leveling, troweling or other equipment within the form.

By vibrating the pipe form as the same rotates by any of the means shown herein, I find that relatively dry mixes can be properly compacted and that a superior product can be produced. Also, it is possible to use lower speeds of rotation of the form with the consequent advantages thereof.

Although the invention has been particularly shown and described, it is contemplated that various changes and modifications can be made without departing from the scope thereof as indicated by the following claims.

I claim:

1. In apparatus for casting concrete pipe including a cylindrical form and means for supporting and rotating the form about its axis, means for vibrating said form during rotation thereof, comprising a wheel having an interrupted peripheral surface, means supporting the wheel for rotation, and means for constantly resiliently urging said wheel against the periphery of the form.

2. In apparatus for casting concrete pipe including a cylindrical form and means for supporting and rotating the form about its axis, means for vibrating said form during rotation thereof, comprising a wheel having an interrupted peripheral surface, a support, a bracket pivotally mounted on said. support, means on the bracket rotatably supporting said wheel, a torsion bar connected to said bracket on its pivotal axis, an arm on said bar axially spaced from the bracket, and a fluid ram anchored at one end and connected to said arm at the other end.

3. Means for vibrating a pipe form as set forth in claim 2 in which shock-absorbing means is interposed between said arm and ram.

4. In apparatus for casting concrete pipe including a cylindrical form and means for supporting and rotating the form about its axis, means for vibrating said form during rotation thereof, comprising a support, a wheelcarrying member pivotally mounted on the support for movement toward and away from the periphery of the form, a wheel having a regularly interrupted peripheral surface for contact with a peripheral surface of the form carried by said member, a fluid-operated ram operatively connected to said wheel-carrying member for urging the same in a direction to bring said wheel into peripheral engagement with said form, and resilient means interposed between said wheel and said ram.

5. In apparatus for casting concrete pipe including a cylindrical form and means forsupporting and rotating the form about its axis, means for vibrating said form during rotation thereof, comprising a support, a wheelcarrying member pivotally mounted on the support for movement toward and away from the periphery of the form, a wheel having a regularly interrupted peripheral surface for contact with a peripheral surface of the form carried by said member, and a fluid-operated ram operatively connected to said wheel-carrying member for urging the same in a direction to bring said wheel into pe ripheral engagement with said form, said wheel-carrying member including a leaf spring section between said wheel and tthe point of pivotal mounting of said wheel-carrying mem er.

References Cited in the file of this patent 

